If you use Google Voice, you probably take advantage of the email notifications when you receive voice mail. Instead of constantly having to go to Google Voice to listen to the message, you can listen to it directly from the notification email while still at Gmail.
1. Go to Gmail and login to your account.
2. Click the Labs icon 
at the upper right corner of the screen.
3. Scroll down the list to the Google Voice player in mail Lab and select its Enable radio button.
4. Click the Save Changes button.
When you receive a notification email from Google Voice, you will see the Google Voice player at the bottom of the message. Click the Play button to listen to the message.
